Brush cutter

ABSTRACT

A cutting tooth having a blade-like cutting section with opposed top and bottom surfaces, opposed front and rear ends defining a length therebetween, and opposed sides defining a width therebetween, a mounting section extending down from the bottom surface of the cutting section with at least a top portion of the mounting section adjacent the cutting section defining a width smaller than that of the cutting section, the mounting section having laterally extending retaining members spaced from the cutting section and adapted to be retained in a mounting block, at least a quarter of the length of the cutting section extending past a front of the mounting section, with the front end of the cutting section terminating in a cutting edge.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. application Ser. No.12/924,862 filed on Oct. 8, 2010, which claims priority on U.S.Provisional Patent Application No. 61/344,453 filed on Jul. 26, 2010,the entire contents of which is incorporated herein by reference.

TECHNICAL FIELD

This invention relates to a cutting tooth for a brush cutter. Theinvention further relates to a cutting assembly for a brush cutter. Theinvention also relates to a brush cutter incorporating the cuttingassembly.

BACKGROUND OF THE ART

Brush cutters employing a cylindrical, rotatable, drum with cuttingassemblies mounted on the drum, the drum mounted on the front of avehicle or on a boom on a vehicle, are known. The cutting assemblieseach generally comprise a mounting block fixed on the drum with acutting tooth detachably mounted on the block. Since the mounting blocksand the teeth thereon are exposed on the surface of the drum, the brushcutters require frequent maintenance both in replacing damaged elementsof the cutting assemblies, and in keeping the cutting teeth sharp.

Brush cutters are known which employ a cylindrical rotatable drum withannular, spaced-apart, protective collars mounted on the drum, and witha cutting assembly mounted partly within the peripheral edge of eachcollar so that at least part of the assembly is protected. However theassemblies extend laterally from the collars and the tooth assembliesoften make initial contact with the unsupported, lateral, sections ofthe assemblies during cutting resulting in frequent damage to theassemblies and/or collars.

Brush cutters are also known which employ a cylindrical rotatable drumwith annular, spaced-apart, protective collars mounted on the drum andwith cutting assemblies mounted between adjacent collars on the drum.The cutting assemblies have a tooth mounted on the front of a mountingblock, the block fastened to the drum and the collars and normally belowthe peripheral edge of the collars. The tooth extends up from the frontof the block and is angled forwardly above the collars. The mountingblocks are well protected between and below the outer edge of thecollars. The teeth however, extend above the collars and are bent toextend upwardly and forwardly. If the teeth extend too far upwardlyabove the collars and mounting blocks, the teeth are subject to largebending forces resulting in early failure of the teeth. If the teeth donot extend too far above the collars and mounting block, the teeth havea small bite when cutting brush and thus are not very efficient.

SUMMARY

It is the purpose of the present invention to provide an improvedcutting tooth for a brush cutter which tooth, when mounted on the brushcutter, will: increase the life of the tooth, allow for easier toothinstallation and replacement, increase the efficiency of the brushcutter, and reduce maintenance. It is a further purpose of the presentinvention to provide a cutting assembly for a brush cutter,incorporating the improved cutting tooth in a mounting block, whichassembly will easily yet securely mount the tooth while locating it inan efficient cutting position. It is a further purpose of the presentinvention to provide a brush cutter incorporating the tooth and thecutting assembly in a manner to allow efficient cutting with the toothable to take larger ‘bites’ of the brush than normal making the machinemore efficient. It is another purpose to have the brush cutter positionthe teeth for easy replacement and mounting and for easy sharpening. Itis a further purpose to have the brush cutter position the teeth in amanner to have the cutting section of the tooth approaching a tangentialposition relative to the peripheral edge of the collars so that thecutting edge tends to retain its radial distance from the center ofrotation of the edge even after numerous sharpenings which shorten thetooth.

In accordance with the present invention, a cutting tooth is providedhaving a blade-like cutting section integral with a mounting section onthe tooth. The cutting section is spaced from the mounting section by aconnector section and extends forwardly of the mounting and connectingsections to terminate in a cutting edge. The cutting tooth is mounted ona mounting block to form a cutting assembly for a brush cutter. Themounting block is a parallelepiped adapted for mounting between adjacentprotective collars on a brush cutter drum. The block is mounted at theperipheral edge of the collars above the surface of the drum. Thecutting tooth and mounting block are designed to have the cutting toothquickly and easily, yet extremely securely, mounted in the mountingblock. The manner of mounting of the tooth on the block makesreplacement quick and simple. The cutting tooth is mounted to have thecutting section above the mounting block with the cutting sectionextending forwardly of the mounting block. With the assembly mounted onthe protective collars, the cutting section of the tooth, located abovethe collars, allows the tooth to engage and cut more of the brush oneach rotation making it more efficient. The tooth is mounted to have thecutting section generally tangentially located with respect to thecutting circle described by the cutting edge of the tooth duringoperation. Cutting and impact forces are thus transmitted mainly incompression against the cutting section. The tangential and extendedposition of the cutting section on and from the mounting block increasesthe ability of the cutter to grasp more brush thus increasingefficiency. It also positions the cutting edge in a more exposedposition making sharpening easier. The tangential position also ensuresthat the cutting edge remains in generally the same radial locationafter sharpening thus minimizing any reduction in efficiency due toshortening of the blade. The tooth is preferably spaced radiallyoutwardly from the periphery of the collars at least about a distanceequal to half the thickness of the tooth. The cutting section of thetooth is further sized and positioned to have the cutting edge at leastabout a third of the length of the cutting section in front of themounting block.

The invention is particularly directed toward a cutting tooth having ablade-like cutting section, a mounting section extending down from thebottom of the cutting section, the mounting section narrower and shorterthan the cutting section, and generally centered with respect to thecutting section, the mounting section having laterally extendingretaining means spaced from the cutting section, at least a quarter ofthe cutting section extending past the front of the mounting section andterminating in a cutting edge.

The invention is further directed toward a cutting assembly having: amounting block for attachment to a brush cutting drum, the block havinga front surface and a top surface, a slot extending into the blockrearwardly from the front face, the slot open in the top surface, theslot having a laterally enlarged area spaced from the top surface; acutting tooth having a plate-like top cutting section, a mountingsection extending down from the bottom of the cutting section, themounting section narrower and shorter than the cutting section, andgenerally centered with respect to the cutting section, the mountingsection having laterally extending retaining means spaced from thecutting section, the tooth connectable to the mounting block by slidingthe mounting section snugly into the slot in the block with the cuttingsection resting snugly on the top of the block and the retaining means,in the laterally enlarged area, preventing the tooth from moving upthrough the slot, the cutting section, when the tooth is mounted on theblock, having at least a quarter of its length extending forwardly fromthe front of the block and terminating in a cutting edge.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the brush cutter;

FIG. 2 is an end view of the brush cutter;

FIG. 3 is a detail side view of a collar;

FIG. 4 is a cross-section view taken along line 4-4 in FIG. 2 showing acutting assembly mounted on two adjacent collars of the brush cutter;

FIG. 5 is a perspective exploded view of the cutting assembly;

FIG. 6 is a front view of the mounting block;

FIG. 7 is a side view of a mounting block;

FIG. 8 is a cross-section view of the mounting block taken along line8-8 in FIG. 6;

FIG. 9 is a front view of a cutting tooth;

FIG. 10 is a side view of the cutting tooth;

FIG. 11 is a perspective view of a modified cutting assembly;

FIG. 12 is a perspective exploded view of the assembly shown in FIG. 11;

FIG. 13 is a perspective view of another modified cutting assembly;

FIG. 14 is a perspective exploded view of the assembly shown in FIG. 13;and

FIG. 15 is a view similar to FIG. 8 with a modification to the mountingblock and cutting tooth.

DETAILED DESCRIPTION

The brush cutter 1 of the present invention, as shown in FIGS. 1 to 3,has a rotatable drum 3. The drum 3 includes a central, tubular member 5having a cylindrical surface 7. Annular collars 9 are mounted on thetubular member 5, the collars of equal size and equally spaced-apart andtransverse to the longitudinal, central axis 11 of the tubular member 5.Each collar 9 has an inner circular periphery 13, sized to just receivethe member 5 there through, and an outer periphery 15. The outerperiphery 15 is also preferably circular but it could also have helicalsections. Each collar 9 is welded onto the surface 7 of the tubularmember 5. The drum 3 is mounted at its ends in any well-known manner ina frame (not shown) that carries the drum and the drum is rotatable inthe frame about its axis 11 by suitable drive means, (not shown).

Each collar 9 has at least one first cut-out 17 extending radiallyinwardly from the outer periphery 15 of the collar. The cut-out 17 has agenerally semi-circular shape and extends nearly halfway into thecollar. A second cut-out 19 is located behind and adjacent to each firstcut-out 17 in each collar 9, the second cut-out 19 intercepting the rearof the first cut-out 17 and having a roughly rectangular shape. Thesecond cut-out 19 is generally transverse to a radial line 23, extendingfrom the axis 11 of rotation of the drum, the radial line 23 bisectingthe cut-out 19. The first cut-out 17 helps in chip dispersal duringoperation of the brush cutter. The second cut-out 19 is used to mount acutting assembly 25 on adjacent collars as will be described.

Each pair of adjacent collars 9 supports at least one cutting assembly25 between them. Each cutting assembly 25 is mounted in the secondcut-outs 19 of the adjacent collars, which cut-outs are aligned, as willbe described. Thus, as shown in FIG. 1, adjacent collars 9A-9B support acutting assembly 25A between them. Next adjacent collars 9B-9C support acutting assembly 25B between them. Next adjacent collars 9C-9D support acutting assembly 25C between them. Each pair of adjacent collarssupports at least one cutting assembly. Each cutting assembly isangularly displaced relative to the immediately adjacent cuttingassemblies. The amount of angular displacement can vary.

Each cutting assembly 25 includes a mounting block 27 having a generallyparallelepiped shape as shown in FIGS. 4 and 5. The length of the block27 is about the same as its width and the block can have a thicknessabout half its length. The block 27, as shown in FIGS. 6-8 has a slot 29extending rearwardly from the front surface 31 of the block. The frontsurface 31 of the block is the end of the block facing the direction ofrotation of the block when the brush cutter operates. The slot 29extends more than halfway into the block, towards the trailing end 33 ofthe block. The slot 29 opens in the top surface 35 of the block. Theslot 29 has retaining means 36 for helping retain a cutting tooth in theslot. The retaining means 36 can comprise a wider portion 37 in the slotthan the remainder 39 of the slot. The wider portion 37 preferably is atthe bottom of the slot 29. The slot 29 is shaped to hold a tooth in theslot against centrifugal forces during rotation of the drum. The slot 29shown has an inverted ‘T’ shape but other shapes achieving the sameresult as the ‘T’ slot can be used. The sides 41 of the block 27 areundercut at their bottoms to form shoulders 43 just above the bottom 45of the block. A threaded hole 47 extends through the trailing end 33 ofthe block through an end wall 49 opening into the slot 29.

The mounting block 27 is adapted to be mounted between two adjacentcollars 9, having the shoulders 43 resting on the bottom edge 51 of thesecond cut-outs 19 as shown in FIGS. 2 and 4. The block 27 is welded tothe collars 9 about the cut-outs 19 with the block being welded to thetwo collars 9 at the shoulders 43 and at part of its leading andtrailing ends 31, 33. When welded, the top 35 of the block 27 isgenerally aligned with the outer peripheries 15 of the collars 9 asshown in FIG. 2. When attached to the collars, the block 27 is spacedfrom surface 7 of the tubular member 5 forming a chip dispersal gap 53between the block 27 and the tubular member 5.

The cutting assembly 25 includes a cutting tooth 57. The cutting tooth57, as shown in FIGS. 9 and 10, has a blade-like cutting section 59 atthe top, and a mounting section 61 extending down from the bottom 62 ofthe cutting section 59. The mounting section 61 is narrower and shorterthan the cutting section 59 and centrally located with respect to it.The mounting section 61 has lateral retaining means 63 spaced from thecutting section 59. The retaining means 63 can be in the form of flanges65 at the bottom of the mounting section 61 extending laterally from itssides. The mounting section 61 fits snugly in the slot 29 with theflanges 65 fitting in the bottom section 37 of the slot. The cuttingsection 59 rests snugly on the top 35 of the mounting block 27 with acutting portion 66 projecting forwardly of the block. When the tooth 57is mounted in the block 27, a threaded hole 67 in the rear of theconnecting section 63 is aligned with, and adjacent, the threaded hole47 in the end wall 49 of the block 27. A bolt 68 connects the tooth 57to the block 27.

The cutting section 59 has a generally flat blade shape, is about aswide as it is long, and is generally straight. The cutting section 59 isrelatively thick, about a half inch, but its thickness can range betweenabout three sixteenths of an inch and five eighths of an inch. The frontof the cutting portion 66 is bevelled to form a cutting edge 73.Preferably the top surface 75 is bevelled slightly at the front of thecutting section as shown by bevel surface 77. Bevel surface 77 is angleddown from the top surface 75 by an angle θ of 8-10°. This angle providesclearance for the cutting section when cutting to minimize drag. Thecutting section 59 is also bevelled up from the bottom surface 62 by abevel surface 81. The bevel surface 81 extends upwardly at an angle Øbetween 45-50°. The bevel surfaces 77, 81 meet about a third of the waydown from the top surface 75 to form the cutting edge 73.

At least about a quarter and preferably about a third of the cuttingsection 59 extends past the front of the block 27 connecting section 63.Preferably the projecting portion 66 of the cutting section 59 thickensslightly from the rear to the front and is undercut at the front asshown at 83. The thickening raises the cutting edge 73 well above thecollars 9 and the undercutting provides greater access to the cut-outs17, 19. The tooth 57 is positioned and sized to have the cutting edge 73follow a circular path 87 that has a radius R1 one half to one inchlonger than the outer radius R of the collars 9 as shown in FIG. 2.

The cutting section 59 of the tooth 57 is shown and described as beingrelatively straight but it can be curved down slightly at the front, asshown at 89 to minimize drag during cutting. The cutting section 59 canalso be curved slightly transverse to its length if desired. The cuttingsection 59 is made long enough to ensure that it is securely attached tothe mounting section 61 and yet long enough to project past the block 27for at least a quarter of its length. Having the cutting section 59above the block 27 and the collars, and extending forwardly generallytangentially from the block allows the brush cutter to have a deeperbite when rotating and also allows it to better gather brush to be cut.Having the tooth extending generally tangentially and forwardly of theblock also allows it to be sharpened many times without greatly changingits depth of bite so it retains its efficiency. The cutting edge 73 doesnot move too far inwardly from the original cutting circle 87 as thetooth shortens when sharpened. The tooth is also generally aligned withthe cutting force exerted on the tooth, the tooth taking the cuttingforce primarily in compression. The arrangement is also protective ofthe mounting block while locating the tooth in an efficient cuttingposition.

The tooth 59 described is preferably integrally forged or cast as asingle unit. Alternatively, the cutting section can be separately formedfrom the mounting section. In one embodiment, shown in FIGS. 11 and 12,a platform section 91 is provided on the top of the mounting section 61to receive the cutting section 57A. The platform and mounting sections91, 61 form an integral unit 93 which can be forged or cast. The cuttingsection 57A in this embodiment can be slightly thinner and can be weldedonto the flat top 94 of the platform section 91. In another embodiment,shown in FIGS. 13 and 14 the cutting section 57B can be bolted onto theflat top 94 of the platform section 91 with a bolt 95. The platformsection 91 could have a shoulder 97 at its end against which the cuttingsection 57B abuts. In both embodiments using a platform section thecutting tooth is more plate-like than the forged cutting tooth. Theplatform not only serves to mount the tooth on the block but also servesto raise the cutting edge of the tooth relative to the collars toprovide more efficient operation.

To improve stability for the tooth, the bottom section 37′ of the slot29′ in the mounting block 27′ can taper slightly from the leading end31′ of the block, narrowing toward the trailing end 33′ as shown in FIG.15. More specifically, the upper surfaces 101 of the bottom section 37′tapers toward the bottom surface 103 in moving toward the trailing end33′. The bottom flanges 65′ on the mounting section 61′ of the tooth 57′are also tapered from its leading end 69′ toward its trailing end 67′.More specifically, the upper surfaces 105 of the flanges 65′ are taperedto the same degree that the tapered surfaces 101 on the lower section ofthe mounting block 27′ are tapered. As a result, the tooth, as itsmounting section 61′ nears complete entry into the slot 29′ in the block27′, wedges tightly into the block between slot portion 37′ and theupper surface 35′ of the block. Impact forces generated during cuttingonly serve to more tightly wedge the tooth to the block.

To further improve stability of the tooth during cutting, the uppersurfaces 111, 113 of the mounting block 27 can be beveled inwardlytoward the slot 29 at a small angle ‘D’ of about fifteen degrees asshown in FIG. 6. The upper portion of the mounting section 61 can haveits sides flare outwardly before joining the cutting section 59 near thesides of the cutting section. The flared sides form bottom surfaces 115,117 that are angled outwardly and upwardly on each side away from theslot at an angle to match the angle of the bevel of the surfaces 111,113. The bottom surfaces 115, 117 of the connecting member 57 will sitflush on the bevelled upper surfaces 111, 113 of the block 27 minimizingside-to-side rocking of the connecting member 57 and the attached tooth57 to either side during cutting. The surfaces 111, 113 can instead beformed on the bottom of the platform 91 if a platform is used in placeof a forged tooth.

The invention claimed is:
 1. A cutting tooth comprising a blade-likecutting section with opposed top and bottom surfaces, opposed front andrear ends defining a length therebetween, and opposed sides defining awidth therebetween, a mounting section extending down from the bottomsurface of the cutting section with at least a top portion of themounting section adjacent the cutting section defining a width smallerthan that of the cutting section, the mounting section having laterallyextending retaining members spaced from the cutting section and adaptedto be retained in a mounting block, at least a quarter of the length ofthe cutting section extending past a front of the mounting section, withthe front end of the cutting section terminating in a cutting edge. 2.The cutting tooth as claimed in claim 1, wherein the retaining membersinclude a pair of symmetrical bottom flanges, one of the flangesextending from each side of the mounting section.
 3. The cutting toothas claimed in claim 2, wherein a distance between the bottom surface ofthe cutting section and a top surface of each flange progressivelyincreases from the front to a back of the mounting section to define atapered shape.
 4. The cutting tooth as claimed in claim 1, wherein thetop portion of the mounting section is connected to the cutting sectionthrough angled surfaces which are angled slightly upwardly and outwardlyfrom the cutting section.
 5. The cutting tooth as claimed in claim 1,wherein the cutting section is a separate member from the mountingsection and fixedly mounted thereto.
 6. The cutting tooth as claimed inclaim 5, wherein the mounting section has a platform section integralwith the top portion and extending laterally therefrom, the top portionbeing fixedly mounted to the cutting portion through the platformsection.
 7. The cutting tooth as claimed claim 1, wherein the cuttingsection and mounting section are formed of a unitary piece.
 8. Thecutting tooth as claimed claim 1, wherein a thickness of the cuttingsection is between 3/16 inch and ⅝ inch.
 9. The cutting tooth as claimedin claim 1, wherein at least a third of the length of the cuttingsection extends past the front of the mounting section.
 10. The cuttingtooth as claimed in claim 1, wherein a rear surface of the mountingsection has a tapered hole defined therein for engagement with a taperedfastener.